Linked Life Data

8289287

Source:http://linkedlifedata.com/resource/pubmed/id/8289287

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1994-2-18
pubmed:abstractText
High-resolution crystal structures of the co-operative dimeric hemoglobin from the blood clam Scapharca inaequivalvis have been determined in the unliganded (deoxy) and carbon monoxide (CO) liganded states. The deoxy structure has been refined at 1.6 A resolution to an R-factor of 0.158 and the CO structure has been refined at 1.4 A resolution to an R-factor of 0.159. These structures reveal details of the structural transitions involved in co-operative ligand binding that involve only a minor rotation of subunits but very striking tertiary changes at the interface. A small number of residues in the F-helix appear to mediate co-operativity in this simple hemoglobin. The oxygen affinity of each subunit appears to be largely dictated by the disposition of phenylalanine 97, whose side-chain packs in the heme pocket in the deoxy state but is extruded towards the interface in the CO-liganded structure. Direct involvement of the ligand-binding heme group is a novel feature of the subunit interface and appears important for intersubunit communication. Ligation alters the conformation of the heme propionate groups along with two interacting residues from the symmetry-related subunit. These two residues, lysine 96 and asparagine 100, link the heme of one subunit with the F-helix of the second subunit in such a way as to influence the ligand affinity of that subunit. The interface is highly hydrated by well-ordered water molecules that are likely to be important in the stabilization of the two structures.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
235
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
657-81
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
High-resolution crystallographic analysis of a co-operative dimeric hemoglobin.
pubmed:affiliation
Program in Molecular Medicine, University of Massachusetts Medical Center, Worcester 01605.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.